Burgers:In a small grill-proof saucepan, mix the sesame oil, red pepper, garlic, and chili garlic sauce until blended. Heat on the grill over medium heat for 2 minutes then remove from heat and steep for another 2-3 minutes. Remove the solids and reserve the flavored oil.
Divide the tuna into thirds. Chop two of the thirds into small chunks and add to a bowl of a food processor. Pulse until finely ground. Transfer to a medium bowl. Chop the remaining third of tuna into 1/4" cubes and add to the ground tuna. Add sesame seeds, mayonnaise and flavored sesame oil from above. Mix well and refrigerate at least 30 minutes. Shape into 6 patties and return to refrigerator. Transfer to freezer 30 minutes before grilling.
Wasabi mayonnaise:Mix mayonnaise with sour cream, salt, green onions and wasabi powder in a small bowl. Refrigerate until ready to assemble burgers.
Daikon Slaw:Bundle julienned daikon in paper towels and squeeze to remove excess water. Add to small bowl with ginger slices, salt, and vinegar and toss to mix.
Assembly:
Heat grill to high heat (or so you can hold your hand 4" above the grate for only 2-3 seconds). Brush patties with sesame oil and grill (with lid open) for 2 minutes each side. Flip carefully. Remove from heat. Turn grill down to low and lightly toast buns. Spread each half of the bun with about 1T of the mayonnaise mixture. On the bottom bun then place a watermelon slice. Place a burger on each watermelon slice and top each burger with 2-3T daikon slaw. Add top bun and serve.

Makes 6 burgers.

Comments

I would love these sandwiched to be a big slab of seared tuna on a bun with the toppings, but that wouldn't make them burgers. I tried to keep the spirit of tuna tartare and keep the beautiful tuna from being horribly overcooked. I think keeping some of the tuna in chunks helps that as well as the texture of the burger.